Method of controlling scale in gas cutting of metals



Patented Aug. 16, i932 I N PATENT orrlcr. j

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My invention relates to the art of as cutting metals which-isextensively em oyed in 11580; I0. 4,493. from the pores of the scale,thereby I the scale to disintegrate and fly of from the the cuttingofslots in ferrousmeta s and re-\ surface of the sup orting metal in theform lates particularlyl to a method and apparatus for preventing t epresence of scale from interfering with'the cutting operation.

The present utility of my invention is in cutting of slots in pipe orseamless tubing for the purpose of making strainers or screen forwellsftherefore, in order to simplify, the

disclosure'of my invention without limiting the scope thereof, I'shallhereinafter describe the invention relative to the gas cutting bf slotsin ferrous metal pipes and tubes, it being understood that t e precepts,of the in-. vention maybe ap lied to the cutting of slots in variousmetal p a'tes and bodies.

It is found that the presence of oxides or scale on the surface of metalwill interfere with the action of a {ct of-cutting gas which. inpractice is enera lyoxygen. This inter-- ference with t e cuttingactionis especially important in the cutting of slots in pipefor the purposeof making a well screen or strain-. er and in the previous practice ithas been customary to remove the oxides or scale from the surface of thepipeso as to leave the area adjacent to the line along which the cut isto be made absolutely clean inorder to prevent interference with thecuttingv of the slots due to the presence of scale. I j, g

My present invention [comprehends a method whereby the'cutting operationmay be conducted in the presence of 'scaletherefore eliminating thenecessity of removing the scale from the pipe, and accordingly re-Thereare a numbero ting of metals due'to the resence of" scale, amongwhich are the containing of moisture in the scale either in the form ofhydrated oxide or water mechanicallyheld in the pores of the scale, andthe difference in expansion and contraction of thescale and the metal onwhich such scale is formed.

Naturally, the high heat produced by the cutting torch or tip causesvolatili'z'ation of the moisture .content-Iof the scale more rapidlythan such a volatilized moisture can escape of flakes. Theseakes areoften thrown diuncover the flame and gas openings thereof before thetorch cani g ln be used. In addition to the presence of moisture .inthescale, therapid application of heat is found to cause disintegrationof thescale and the breaking off of scale particles from the supportingbody of metal.

Anobject of myinvention is to method. and apparatus for control fi f iitin thepresence of a gas cutting operation by heating thescale i'n'thezone surrounding the line along which-a cut is to be conducted for thepurpose of c h rgitionin the scale to avoid the disintegratio thereo andthe cor- :responding unsatisfactory results, when the cutting torch isapplied for. the pu of making a cut in the supporting meta The principalutility of this prelimina heatingoperation is to drive from the sc Qcontent the moisture, which may be h dratcd oxide or moisturemechanically carri by the scale. 1 r

Further objects and vention will be made evident throughout thefollowing part of the specification; Referring to the drawing which isfor illustrative purposes only, 1 Fig. 1 isa vertically sectionedfragmentary view of diagrammatic character showing an apparatus suitablefor practice of my present invention. 5

Fig.2 is a view showing a surface ,of a metal I body, such as a pi e,which has been gas cut inthe presence 0 surface scaleand in accordancewith my present invention, l Fi 3 isja vertically sectioned view to Fig;1 but to reduced scale, showing alternative form of apparatus by whichthe invention may be practiced. v i

advantages of the im- 8 6 mixed with oxygen, or may-be common gydrtf 1g.

t op tion f penetrating 9 wall 16,10; as .to heat the'metal Fig. 4 is anenlarged fragmentary partly sectioned view showing the-conditions encountered in the making of a cut in a metal body having a coating oxide,or scale thereon. 1 In Fig. 1, I show a pipe 11; extending throughanopening 12 in a support 18 which carries 'a preliminary heatingv torch14,. a'

drill motor and a cutting torch 16.

accordance with the art of slottinIg pipe disclosed in my United StatesLetters atent No. 1,666,166, granted April 17, 1928, the mechanism shownin Fig. 1 is capable of first drilling small holes in the ipe,after-which as a rotatable head 21, carrying 'a lural:

ity of tips 22 so that in event one of t e tips, 22 should fail toroperly functionthe head so 21fmay be rotated to bring another tip intoworking position. The preliminary heating torch is equipped with a tip23 from which a flame 24 issues. The fuel employed to produce the flame24 may be acetylene properly carbon ,gas intermixed with airi'In Ihowever I have shown flexible conduits 26 and 26sleading intmth'e torch14 through ractice receives acetylene gas and oxy-' t irough flexibleconductors or tubes simto thoseshown at and 26. r "In Fig. 1 he drill 19is shown during the "pipe 11 and in of the torch 16 a been previouslycut-is shown.

the cutting equipment the strncture 18 is operation of the drillingmechanism and the cutting torch'16. During the drilling opera tiontheheatingflamee issue from the torch. rrounding the hole 81 and when thedrill sp die 17 is raised a cu ting jet of oxygen is directedthrough thehole leftward direction'causing the jet which is 22 ofthe'torch .16 tocut; ,Ifiaalotinthew wofthepi'pelh During sues fromthe P ta; '4 i th Iof 'co:1dn(l:ltmg e roper gaseoussu ces' te torch. Th

heat; p e cutting torch, in accordance with accordance with the.convenient use of a aavaaio the heating of the area aurrounding the bis.

81 by flames issuing from the cutting tore tip 22, the flame QA mayissue from the torch 14 1 so as to play on the surface of the pipe 11 aor rather on the scale or oxide coating'of the pipe. The flame 24 iscontinued throughout the time of the travel of the su port 18 inleftward direction so that an e on ated area on the pipe is heated, thishea being so'positioned that the next hole formed by operation of thedrill 19 will be situated at the rightward end thereof, as indicated at36ofFig.2.

After the hole has-been drilled at 36 there in the heated area 35 isrelatively moved into position of cooperation with.) the cutting torch16 sothat when the cuttfng torch is a ain ofierated'a slot 32 will becut centrally a ong t e heated area which then'occupies the relativeposition indicated at 37 in Fig. 2.

From the foregoing it will be perceived that before the cutting torch 16is operated to cut a slot in. the pipe 11 a zone is heated surroundingthe line along which the cut is to v be made, the heating of this zonebeing eflectiveto greatly reduce or to 'entirelly'prevent disintegrationof the oxide or sca o coati the, pi during the operation of the cut t ngtorc 16, thereby avoiding the-diflicul- I ties heretofore encountered inthe cuttin' of scale thereon and which cu ties ms 40 in which a slot 411s being'cut by a gas jet in' addition to the jet 42 provides heatingflames 44. The pipe 40 .is shown with its customlagg' coating. of oxideor'.sc ale 45. The need by the he'ating'flames 44 and by the cuttingaction'of the jet 42 causes flakes, 4 to break, curl up, or fly oil fromthe oxide coating or scale'45 on the pi 40; As indicated by dotted lines48 in ig. 4 a'flake of ,scale is often carried against the lower end h hthitO of the a ent wit eti 22- dn ll l i oleis shown. Tgthe right of thedrill hole 31, a slot32 which has of thetorch 48 with the result ofeither causing the torch to back-fire or'shutting ofl.

- the proper issue of the heating'flames, or the cutting jet. v

y M invention assimilate-11m such con itions as those justdescribed by'condishow aportion of the pipe wall A j necessary the cleaning ofthe Iwhich results in dehydrati'n the scale and also producing in the zone 0the line of-cut:

disintegration or flaking of-theiscale either as a the resultofvolatilization of moisture there- 81, whereupon the head 13 is movedinreto. Thisconditioning or preliminary heating of the scale isaccomplished before the zone of the line of cut is operated on by theflames and gas issuing from the cutting torch,

In the preferred practice of the invention the scale and the pipeadjacent thereto are heated to a temperature of from 250 F. to 350 R,which is above the boiling point of water, such temperatureaccomplishing the desired effect of dehydrating the scale, con-.ditioning same for the cutting operation.

In Fig. 3 I show an alternative form in which the invention may bepracticed, including a frame 60 relatively movable to a pipe 61, adrilling mechanism 62, and a torch 63 mounted thereon. Into the forwardend 64 of the pipe 61 a burner head 65 is projected on the end of a pipe66 through which gas or a fuel mixture is conducted to the burner head65. The burner head is at all times maintained in a position aheadof thetorch 63 and its flames 6? are directed radially outwardl against thewall 68 of the pipe 61 so as to eat the pipe and likewise the scale oroxide coating carried thereon preliminary to the cutting operation to beaccomplished by the cutting torch 63.

During the operation of the device shown in Fig. 3 a circulation of airis maintained in leftward direction through the pipe 61 by a suitableexhaust fan located at the left end thereof, the air entering the pipethrough the last few rows of slots 69 which have been reviously cut, asindicated by arrows 70 and Sowing leftwardly through the pipe 61 andaround the burner head 65 as indicated by arrows 71.

The mechanism disclosed in Fig. 1 beats only limited areas or zones ofthe scale and pipe surrounding the line of cut to be folowed by thecutting torch and the form of mechanism shown in Fig. 3 heats the entirewall of the pipe, this latter practice requiring a larger amount ofheating but in a measure compensating therefor by the use of a verycheap fuel in the burner head 65.

Although I have shown a simple and practical embodiment of my inventionit is recognized that some of the elements thereof may be replaced byother elements capable of performing the same functions in a.substantially equivalent manner; therefore the invention is not to belimited by the details of the foregoing disclosure but should beaccorded the full scope of the following claims.

I claim as my invention:

1. A method of controlling scale in gas cutting of metals having scalethereon, com-- heating the scale in the zone of the prising cut to emade to a temperature between 250 F. and 350 F. preliminary toapplication of the cutting torch to make such cut and at a' timesufiiciently ahead of said cut to permit complete conditioning of saidscale against disruptive action of the scale in ofthe cutting plane.

the presence 2. A method of controllin scale in gas cutting of metalshavin scale t ereon, com rising the application 0 an initial heating ame1 in a manner to heat the scale in the zone of the cut to be made to atemperature between 250 F. and 350 F. preliminary to application of thecutting torch to make such cut and at a time sufliciently ahead of saidcut to permit complete conditioning of said scale against disruptiveaction 0 the scale in the presence of the cutting flame.

3. A method of the character described for cutting a slot in a metalwall, including: heating the metal in the zone of the slot to a.temperature between 250 and 350 F.; drilling a starting hole in saidwall in said heated zone; and, by use of a jet of cutting gas,- cuttinga slot startin at said hole and extending within said heate zone.

4. A method of'the character described for 7 cutting a slot in a metalwall, including:

heating the metal wall to a temperature between 250 and 350 F.; drillinga startin hole in said metal wall; heating the meta surrounding saidhole to a temperature for producing combustion of the metal in thepresence of a cutting gas; and, by the use of a jet ofcutting gas,cutting a slot in said wall starting at said hole.

In testimony whereof, I have hereunto set my hand at Los Angeles,California, this 10th day of April, 1930.

' CLARENCE J. COBERLY.

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